Machine and method for building electrical condenser stacks



Oct. 20-, 1925.

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Oct. 20, 1925.

W. H. PRIESS MACHINE AND METHOD 1 012 BUILDING ELECTRICAL CONDENSER STACKS Fild Aug. 2. 1921 I3 Sheets-Sheet 2 Oct. 20, 1925.

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w. H. PRIESS MACHINE AND METHOD FOR BUILDING ELECTRICAL CONDENSER STACKS Filed Aug; 2, 1921 13 Sheets-Shut 12 avwmtoz MlliamZRiaSS 11M Elihu WW Oct. 20,1925. 1557,7124

W. H. PRIE SS IACHINB AND IETHOD FOR BUILDING ELECTRICAL CONDENSER STACKS Filed Aug. 2, 1921 '13 Sheets-Sheet 1s Patented Oct. 20, 1925.

} UNITED STATES WILLIAM H. rnInss, or BELMONT, MASSACHUSETTS, AssIGNoia TO WIRELESS srre PATENT. OFFICE.

CIALTY APPARATUS COMPANY, or BOSTON, MASSACHUSETTS, A CORPORATION 017 H NEW YORK.-

MACHINE AND METHOD rou BUILDING ELECTRICAL CONDENSER STAGES.

, Application filed August 2', 1921. Serial No. 489,156. 1

T 0 all tvhom it may concern:

Be it known that 1, WILLIAM H. PRIEss, a

citizen of the United States of America, and

The machine of the present invention,

either taken as a whole or taking its several features separately, is of general application and may be used for building stacks comprising sheets of different kinds of material which are used for different purposes. .In particular, however, the machine of the present invention is especially adapted for the manufacture of electrical condensers of the sheet type and especially of the type which] utilizes mica as adielectric.

Electrical condensers of the sheet type consist of alternate layers of foil and dielectric in which, in most cases,.the foil is arranged to project beyond the mica alternately at opposite sides to provide terminals for connecting, and thecondensers are provided with margins to prevent leakage between the foil on one side of the dielectric and the foil on the other side of the dielectric. Condensers are of general application. SODZIQILIQ of the transinitting' or high potential type for use in radio transmission; others are used for protective pur poses and in ignition systems. In most cases, the stack istreated, either during the build ingoperation or after completion, with 'an insulating material such as parafin or varnish. By way of exemple, condensers, such as used in transmitters of radio circuits, have been in the past built and constructed in the manner shown and described in the pending application of Pickard, S. N. 380,919, filed 12 May, 1920, and in a pending application of Priess, S. N. 456,903, filed 30 March, 1921.

The process employed in the manufacture of condensers especially adapted for ignition work, known as magneto condensers,is disclosed and described in a pending application of. Priess, S. N. 377,977, filed 30 April,- 1920. The processes now in use. in the manufacture offcondense-rs are manual, and the accuracy of building the stack'and of alining the foil and dielectric depends largely upon the skill, of the operator. It has been found ,I that manual processes result in a product having more or less lackof uniformity, in,-"

accurately laid alternate conducting and mica sheets, and nonuniformity in varnish ing the parts of the condensers; The manual process, moreover, is slow and comparatively expensive.

An object of previously has been done by hand.

In the present embodiment of the inven tion, the machine comprises three operating positions with means for successively f and continuously carrying the material acted upon, such as, the mica sheets, from and to general these positions of operation. The plan of the machine is as follows.

One of the operating positions comprises a hopper or magazine-containing sheets of the present invention is to provide a machine for doingthe work which" mica of the desired size and a pickup mech-f anism. At another position is located mechanism for'varnishing or treating the-mica" with a suitableinsulating material. At a" third position is located the mechanism for alternately laying the mica and foil sheets.

Mechanism is provided for removing the f mica sheets from the hopper, transferring;

them to the varnishing apparatus, and then depositing them in a building stack where foil sheets are deposited upon them;;, The Whole operation is continuous,and the same; source of power or primemover drives the several mechanisms. for the several mechanisms are so reTated that the mica will-Abe; carried around and The transmission earsf treated or acted upon by the. several'mechanisms successively. r

The several features of the machineabove mentioned may be utilized in whole 'orin part in a practical embodiment ofw'the'con denser machine, and may also have general application to other uses. For example, they mica hopper and pickup device for the mica may be usedfo-r carrying mica from the hopper to a point 'otap-plic'ation where an entirely different process is applied to it,

suchas dieing or cutting the mica. In some 7 sheets so that they will project alternately fromtfopposite: sides of the. mica .to form the terminals above mentioned. Inthe present embodiment of the invention, between each operation of the foil dieing and depositing mechanism, the standzon which the stack is beingbuiltis rotated.180, as more fully describedhereinafter. The varnishing or wax applying might also be done in ways other than thatdescribed herein.

The machine of the present invention, in so vfar-as it rel'ates to the mica pickup device,

utilizes the natural qualities of the micawhereby it may be flexed or bent to remove it from the bottom of the magazine stack. Furthermore, duringthe varnishing operationfaseach sheetof mica is pulled out from between varnishing jaws, a bead of varnish 1s formed'upon one edge-of the mica atjithe end which is pulled out last, and this bead'is ii tili-zed for distributing the varnish uniformly throughout the stack, since 180 motion of the stack building stand bet Ween the successive laying ofmicafilmscauses the beads to be placed alternately. Since the portion o f micacovered'by the mica-removing j'aWsis not varnished, the bead of varnish'onthe edge of' the adjacent film of mica covers this unvarnishedportion, the films being alternately placed. The result is "to produce very even distribution of varnish throughout the stack, and on baking under spring pressure providesa condenser whose margin will be filled with baked -1,

In the accompanymg drawlngs, Figure 1 is atop planview of the complete machine.

Fig. 2 .is a horizontal section of the com plete machine on the line 2 2. of Figs. 8, 6, 11,"l2. and 13 looking in the direction. of thearrows. I Fig. 3. is a detailed vertical section on the line3-3 of "Fig.. 1 lookingin the direction oii the arrows, Fig. 3' being on somewhat larger scale than that of Fig. 1.

Fig. tis "a. fragmentary plan view, partly in section, of the mica magazine device on an enlargedscale.

Fig. 5,.is avertical section ofthe same on the line-5a5 of Figlooking in the direction of the arrows, theuparts being in. the position .they..assume when a sheet of mica is about-to be withdrawn from the magazine.

Fig.56fisfa detail verticalsection on a somewhatlarger scale, onthe line 6-6 of Fig.

tion of'a part of the foil feedingmechar.

nism on the line 10-10 of Fig.1 looking in the direction ofthe. arrows. I

Fig. 11 is an end elevation, partly. in section, of. the drum of Fig. 10 asviewed from the right of Fig. 10.

F'g. 12 is anenlarged vertical detail section of. the stack-building and toil-laying mechanism on the line 1212 of Fig; 1 look.- ingiinthe direction of the arrows.

Fig. 13 is a vertical detail section of the stack-building and foil-depositing mechanism transversely of Fig. 12 and on the line 13-13 of Fig. 1, looking in the direction of the arrows.

Fig. 14 is an enlargeddetail of a fragment of Fig. 13 with the moving parts in the alternate position.

Fig. 14 is. a diagrammatical view of a portion of a stack. as built by the machine of the present invention.

Fig. 15 is a horizontal. fragmentary section on the line 1515 of Fig. 13, looking in the direction of the arrows, showing the rotatable stack building stand on an enlar ed scale.

Big. 16 is a vertical section ofa part of Fig. 15 on the line 16-16 ofFig. 15, looking in the direction of the arrows.

Fig. 17 is a horizontal plan section of the stack building stand illustrating the method in which the mica is placed in position therein.

Fig. 18 is a side elevation partly in sec.- tion of the stack building stand. illustrating with Fig.1? how the mica is inserted in the stand.

Fig. 19 is an enlarged detail plan view of the counting mechanism shown in F ig- 2,

but with the parts in the alternate position.

Fig; 20 is a diagrammatic view of the electric controlling circuitused. on the machine.

Fig. 21 is a supplemental mica alining device, associated with the mica hopper, the view being a vertical section on theline 2121 in Fig. 22.

Fig. 22 is a top plan view of the construction shown in Fig. 21.

Fig. 23 is a rear elevation of the upper end of the construction shown in Fig. 22.

Fig. 2 1 is an end elevationof the construction shown in Fig.;23, looking from the ri ht. V

Tieferring to Fig. 1,"the-m1camagazine or hopper with its controlling or pickup varnishing mechanism is indicated general- 1y at V, while thefoil dieing and foil-laying mechanism is indicated at F. The mica-carrying mechanism is indicated generally at .C. The three mechanisms M, V and are arranged 120 apart around a rotatable table 10 a part of the'carrying mechanism C. ,The several mechanisms above briefly referred to are actuated by a worm 1 driven from a suitable source of power or by motor .1 and meshing with a worm wheel 2 on a mainshaft 3. (See Figs. 2, 3 and 6.) The motor and transmission mechanism, as well as the several mechanisms M, V, F and C, are; mounted on a suitable framework or support S, which framework comprises a series of tables 231, 230, 241,228, superimposed above each other in spaced-apart relationship and connected by vertical rods 232, 233 and-234.

' Mica cam ingmeclzam'sm U.

The main shaft 3 has secured to it above the table or support 241 (Figs. 2, 3 and 6) a pinwheel- 4 having thereon a pin 5 for driv ing the hereinafter-describedmica-trans ferring mechanism rC. Ajstar wheel 6 is secured to a vertical shaft 7 journaled: in tab1es230 and 241 (Figs. 2, 3 and 6). The

-star wheel 6 comprises four radially-ar-f' ranged slots 6 extending inwardly from the perifery and arranged apart and with intermediate concavecam surfaces 6 adapted to co-operate with a locking cam 4 fise cured to shaft 3 in the horizontal plane-jot thestar Wheel 6 (see Fig. 2). The cam 4 is segmental, being ,cut away as indicated at 4* at a point facing the pin 5. :Withthe pin 5and segment4 in the positions shown 4 in Fig. 2, the segment-4, wh ch has a convex edge, 1s engag ng one ofthe surfaces'6 ;of.

the star wheel 6, preventing the rotation ofthe latter. As the rotation of the pinwheel 4 and segment 4"? continues, the segment will finally disengage the star wheel 6, and the pin 5 willenter one of the slots 6 of the star wheelj asshown at 15, illusg trating another starwheel operating on a similar principle, The gearing above described, -including the .pin wheel 4 and star wheel 6, constitutes what is known as a Geneva gear transmission for imparting an intermittent rot-atary motion to the micacarrying mechanism C, and in this instance the rotatable tabl .10 and themica pickup arms 25, as more fully hereinafter described. -For this purpose, secured to the shaft 7 above the star wheel 6 is a gear; 8.

which meshes with a gear 9, secured, as

- o n; n F g: ,.tet e1 t t b 1 t ble.

having a hearing as indicated at 10 on" the top table support 228, which, for the purpose of receiving the table 10, is provided with central circular opening 10". mechanismis indicated generally at M, the

Bl'y way of example, if the pinwheel 4 has 60 P. M., the star wheel and its shaft WlIl'I'OtELtG 90 in a quarterof a second, im 1 parting to the table 10 through gears 8 and 9 a revolution of 120 in a quarter of a second, the table having a rest in each second err .0m second. I The gear 9 (Fig. 3) is provided with a vertical opening 9 sufficiently large to allow the shaft" 22 hereinafter described to pass through. For moving the hereinafter described arms 25 radially with reference to the table 10, a gear 11 is secured to-the": main shaft 3 and meshes with the gear 12 (see Figs. 2 and 3) secured to shaft 13 mounted vertically upon the supports. To

shaft 13 is also secured a pinwheel 14 havwheel 14 is located between the tables 230 per end of a vertical shaft 17 journaled above the support 230 and in plate 101. Star wheel 16 comprises four radial slots 16 arranged 90 apart and extending in-f 1 wardly from the perifery and with seg- .mental concavities 16 between each adjacent pair of slots 16*.- Secured to shaft 13 in'the plane of'the starwheel 16 is a seg- :mental' locking cam 16 having three radial- 'ly extending arms 16* spaced. 120 apart but extending midway between the pins 15 (Fig. 2

their outer ends, adapted to periodically and successively engage the concavities 16 of the star wheel 16 and lock thesame against rotation. In the position shown in F ig. .2,

it will be noted that one of the pinsv 15 is These arms 16 of the member 16 are provided with curved edges 16 at up I gear 19 secured to a shaft 19, whichhas mounted thereon a gear 20, meshing in turn-- with a gear 21 on crank shaft 22 journaled' 'inthe supports 241and 230 and extending 16 is a gear 18 (Fig. 2) meshing with a 1 above table 10 for imparting intermittentradial' out and in movement to thenarms' 25' as hereinafter described. Gear: 21, although adapted torotate shaftv 22 for imparting radial-movement to the arms 25,- is also slid ably and relatively rotatably mounted on shaft 22 for reasons and by: means hereine after referred-to.

By way. of example, if the inwheel :141has twenty revolutions. per minute' the starwheel 16 will rotate 90 in flofa secondi'aii'd have a rest of of'a secon'd. Gear 21; through the transmission above described. from .star. wheel lfi, will rotate 360- in oiia second and have a of a second rest betweeneach operation. The star wheels G and; 16 open ate alternately to alternately rotate the table '10 and with it the arms 25 and=:th'en move thearms 25' radially out anddn.

and above the table 10'is a'bracket comp-ris ing vertical uprights2 l4e and 1at'e 227-' mounted on uprights 24A and constituting a crank shaft upper bearing plate. The crank shaft 22 between table 10 and plate22 7 is provided with three cranks 22 arranged 120? apart as shown more clearlyin Fig.- 1 (see also Figs. 3 and 6) Links 23='c0nnect a plurality of radially-arranged arms 25 slidably guidedin bearings 2l on table 10 to the cranks 22 The arms 25 are arranged equidistances apart, and inthe present embodiment 120 apart, being slidably-mountand connecting links 23.

an upper movable flared j aw26P-pivoted" by a pin26and-heldnormally in closed'posi tion against the lower jaw by 'means ofaspring 26 coiledaround the pin 26 and engaging the jaws; The upperportion of lower jaw 26? is prov-idedw-ith a transverse vertical rib 26 spaced inwardly fromthe edge of the jaw, forming a ledge26-for receiving the mica m as shown in; Fig- 5 and" also in Fig. 17. Preferably, the outer edges of the jaws 26 and 26" are shaped'to; conform with the edge ofnthe mica with whichit is adapted to engage. as shown in Figs.

17" and 181 The jaws 26 should 'beofsuifi cient width to properly engageor grip the mica.

finger 26 whereby the upper jawmay be opened relative to the lower jaw by means hereinafter described, whenever needed: In Fig.6, a member 26' is illustrated gripping the forward edge; of a piece of mica drawn down from the micamagazine, whilein; Figs: 17*and 18a member 26*isiii-position Referring-to Figs. 1; and'6, secured to counter mechanism.

Each pivoted jaw 26is provided with an upwardlyand rearwardly extending to 1 release. the mica. to the condenser: build .ing stand. Each upper jaw 26 is also pros] vided}: with an inwardly-extending, edge 26* cooperating with the-rib or edge-26 ronthe lower jaw Whe'reby'the edgeof'themicais securely held when being remove'dQ and transferred :to the several locationsto be op erated I upon.

Gomite'r mechanism,

. upona" lowerend" of vertical-"shaft journaled in a suitable support 33 suspendedfrom the tablefifll; (Fig, 3;) ,and alsoghaving a bearing in the support 241. Securedto the gear 83 above the-"hangingsupport 33 is gear 345 Which meshes with-a gear 35 see cured to a vertical shat-e 36 j ournaled in the hanger and-table'24-1. The shaft 36 ex tends above thetabl 241 an-d h'as secured-to" its upper end arotatable disc-37 havingavertical; pin 3 extending upwardly therefrom= constituting v a driving pin of the See al's'ojFig. 1195) Upon each revolution,- 360 for each mica and: foil laid, of fthe-pin'37, it engages-one of the several circumferentially arranged" horizontal pins 38 projecting r-adi'a1ly'fron 1- '105- a units wheel 39 mov-ing-the wheel 39 -a distance oi? 24 unitsw'heel -issecured= to a vertical sha-ft 39. journaled iii-the tables 228* and 241. I A; ratchet wheel 40; 3* and 19) and aresetting'geartl integraliwith the ratchetwheel 40- are rotatab ly mountsdonslia-ftSQ ab0vewheel 39l Pawls 42 'are v pivoted to a' disc-42 keyed or secu-red to the upper portion 413-013 the sh aift 39 and engage the ratchet 40. The ratchet 4L0 andres'et ting gear 41 arerotat'ably mounted upon the shaft 39 but are constrainedby pawls 42; to rotate the shaft 39 whenmoved in one di rection b'ut not when moved in theoppositedirection.- Co'aetingcontacts 44" and? 45 -120-' actuated 'by the counter ;mechani smare pro vidiadfor-controlling the circuit ofthje ma- 7 chine to automatically stop it-(see-Fig. 20');

The contact 44, Figs. 2, 3, and 1'9, projects;

from and is mounted-upon the member 42* which rotates it and is electrically-connected to a slipring; 47ino11nted on the top. A? suitable support 46 on member 42 ofinsulating material, isprovidedflfor supportingcured to a suitable insulating support 49 se cured to the bottom of table 228, engages'the slip ring 47 for connecting it on the circuit. The contact 45, which is arranged to' periodically engage contact 44, is electrically connected 'to a slip ring 50 mounted on an insulating support 51 secured on a vertical shaft 51 journaled in the tables 228 and 241. This slip ring 50 is engaged by a sec ond brush 48 connecting it to the circuit.

and mounted on a suitable insulating support 49 secured to the bottom of table 228. A fifteens wheel 52 is secured to the shaft 51 below support 51. This wheel 52 is provided with fifteen radially-extendinghorizontal pins 53 which are engaged periodical- 1y by a pin- 53 mounted upon and projecting below the member 42 near the perifery thereof for imparting movement to contact 45 (see Figs. '2 and 19). The pin 53' is 12 in advance of contact 44. Upon each revolution of the member 42, the wheel 52 is given a 24 turn. A resetting gear 54 (Fig, 19) is rotatably mounted on the shaft 51 at a point so as to be in the same plane with reset gear 41. To the resettinggear 54 is secured a ratchet 55, Figs. 3 and 19. Pawls 56 are pivoted-to a disc 56 secured to the shaft 51 below ratchet 55, pawls 56 engaging the ratchet 55, whereby the shaft 51 is rotated through pawls 56- in one direction but not in the opposite direction when the resetting gear 54 is moved in opposite di- -rect1ons.

The means for actuating the resetting gears is described hereinafter. In order to maintain the shafts 39 and 51 with. their counters in fixed position when not in operation, there are provided at their lower ends counter detents 57, Fig. 3, with which engage the spring pressed fingers 58. These counter detents 57 have a plurality of depressions 57 in the perifery thereof. with which depressions the spring fingers 58 coact, whereby the shafts are held in fixed position when not in operation, although the spring fingers 58 allow the rotation of the shafts when actuated by the pin wheels. Reset racks 59 and 60 engage respectively, when actuated as hereinafter more fully described, the fifteens wheel reset gear 54 and the units wheel reset gear 41, the racks Y59 and 60 being provided with teeth upon their outer edges at an intermediate portion thereof adapted to engagethe gears 41 and 54. In Figs. 2 and 3', the racks are shown in inoperative position out of engagement with the reset gears, while in Fig. 19 they are shown in operative position in engagement with the reset gears. The racks 59and 60 are slidably or adjustably secured upon opposite edges of a support 61 in themanner of a slide rule. and are retained together against support 61 by means of aguiding support 61" secured to table 241. Suitable vertical guide screws 62, one of. which isse secured "to table 241", extend through longitiidinal slots 62 inthe reset rack support 61 for maintaining. the position of the racks and guiding them. To the rear end of the .member 61 is secured a support block63, which slides on table 241, for supporting the racks 59 and 60 above the plane of the table 241 and in the plane of the reset gears, 41 and 54, ,Theraclis 59 and 60 can be independently adjusted by looseningthe detent or crosspiece 63 adjustably secured to the support 63 by a screw and provided with projections 63*. the detent 63 co operate with a 'plurality'ot holes or depressions 63 on. the racks and bearing suitable numerals indicating the number of sheets to be stacked. As

an example of an embodiment of the resetting mechanism, the resetting gears 41 and 54 may'have, say, 30 teeth each. ,The rack 59 may have 38 teeth, while'rack 60 may have on theresetting gears, so that each rack is capable of giving a complete'revolution" to its resetting gear. On the rack 59, behind the teeth of that rack, are 15 holes 63 arranged in the same straight line and equally spaced. The distance between the centers of adjacent pairszof holes is equalto twice the rack pitch.. In like manner, the rack The projections 63 on v 36 teeth. In. any, case, there should be more teeth on the racks than .90

60 has 15 equally spaced holes 63 in the while the holes'63 of rack 60 arenumbered v 0. 1 to 14. By properly adjusting the racks 59 and 60- relatively' to each other after the machine is started by actuatinigof the racks as a unit, it will automatically stop after any desired number ofoperations within the range of'themachine and depending on the position of the member 63' relative to the holes on the two racks. When'the sum of 'the readings connected by c'rdsspiece 63 is O or multiples of 15. their sum directly indicates the numberpf operations of the machine before stopping. When the desired number of operations before stopping is not amultiple of 1 5, the machine will stop after the number of operations indicated by the sum of the numbers connected by member 63 less 15. For example, when. the racks are arranged as shown in -Fig. 19,'the machine will '"stop after" 141" operations (+615:141).-" To'cause the machine I to stop after'1-80. operations flbeinga multiple of 15) set the racks 59 and 60 so that member 63 is on 180 of, rack 59 and on of rack 60. After the racks are adjusted to position member 63 at the desired holes 63, the racks are actuated as a unit to the position shown in Fig. 19 separating contacts 44 and 45 through gears 41 and 54 and then released, the ratchets allowing the return without affecting the position of the contacts 44 and 45. The machine will then automatically stop after the indicated number of operations, for exampl 141 operations. The means for actuating the reset HIBChELDlSIH'CllSClOSBd in Fig. 19 will be described more fully hereinafter.

When the contacts 44 and 45 engage after a predetermined number of operations as indicated and determined by the positions of theracks on the support 61 and the machine is to be stopped, an electromagnetic lock 64, Figs. 3and 20, comprising a magnetic coil 64*- in the circuit of the machine and controlled by contacts 44 and 45 and a movable plunger armature 64 .pressed forward towards the shaft 3 by means of a spring 64 operates to lock the machine againstmovement. During the operation of the machine, however, the plunger is held inthe position shown in Fig. 3 and Fig. 20. When the machine is to be automatically stopped, the plunger 64' is released, the coil '64 being shortcircuited by contacts 44 and 45, andengages a co-operating locking member 65 secured to the shaft?) to rotate there with and provided with an opening 65 therein. The lock 64, 65 in 'co-operation with the magnetic brake hereinafter more fully described will definitely stop the machine when the plunger 64 enters the opening. 65". which occurs after pin 37 disengages the counter wheels to allow the subsequent operation of the resetting means.

Mica magazine and 'pic lc up mechanism M. .ReferringtoFigs. 1, 3. 4 and 5, there is .Theme'mbers 66 constitute a support fora I transversely arranged tripping device 67 pivoted at 67 a between the members 66 ad'i acent' their innerends. The tripping device 67 hangsdownward into the path of movementofthe upward andrearwardly extending fingers 26 of the gripping members 26 -:oftheseveral members 25. The jaw trip 67 of their engagement therewith, and when they close, after passing the trip, rip a piece of mica as shown in Fig. 5. Sn the return movementiof the jaws 26, the trip 67 yields to allow their removal.

Arranged transversely of the members 66 is a vertically and angularly arranged member 69 which constitutes the front guide or abutment for the mica stack 7 0' supported in a magazine 71. The bottom of the stack rests upon an upwardly and inwardly extending stack base 7 2 mounted upon the top ported over sub'stanti-ally'about one-half of its bottom surface. The weight of the stack as shown in Fig. 3 (on which may be placed an additional weight not shown, if so desired, for maintaining pressure on the stack) is suflicient to hold the stack on the semibase 72, the lower sheets of mica being in engagement with the vertically-extending guide or abutment 69,- which is arranged at right angles to the surface of the part 72. The stop or abutment 69 serves-to aline the adjacent edges of the mica sheets and prevent more than one sheet from being drawn out at a time. The magazine 71'is secured to the base 72 by means of angles 71, and comprises a back 71 and sides 71 which are flared out at their forward vertical edges 71 The forward edges '71 engage the member 69 and the sides 71 extend beyond and below the base 72 as indicated at 71". The stack 70 is supported at a slight angle to the horizontal as shown, so that when a mica sheet is lowered as hereinafter described, its forward portion will be substantially horizontal and suitably positioned to be gripped by the members 26. In order to draw down the lowest sheet of mica in the stack 70 to a position where it isacceSsible to be gripped by the members 26 as above described, there is provided means which is movable into engagement with the bottom sheet of'mica to drawit dowmandi-n the present embodiment this means involves the use of suction or-a vacuum. For-this :purpose, a vacuum cup support 7 3'extendstransversely beneath the members 66' and below the stack 7 O as shownfmore clearly-in Figs. 4-and 5, and is provided at its outer ends with upturned ears 73 pivoted in angular bearings 74 secured to the base 228. The axis of the vacuum support 73 ison a line coinciding with the inner edge 72 of the base 72, thereby allowing a full and free bending or flexing of the individual mica sheets as they are brought down. Upon the vacuum support 73 is mounted a vacuum cup 73 having a passage 73 therethrough communicating with a passage 73 in one bearing 74 of the vacuum support 7 3. The vacuum cup' 7 3 may have any desirable shape. The upper edge which is to engage the mica is provided with a cushion 73 of relatively soft material such as rubber in order to better engage the mica and provide air-tight contact. The passage 73 is connected by means of a rubber tube 75 (Figs. 1 and 3) with a valve mechanism controlled as hereinafter described and adapted to alternately connect and disconnect the vacuum cup 73 with suitable evacuating mechanism (not illustrated) and with the normal atmosphere. This vacuum mechanism may consist of any well-known'means of produc-' ing a vacuum and maintaining it. hen the vacuum cup 73 is raised against the bottom sheet of mica by the mechanism hereinafter described and the vacuum applied, the sheet of mica or other material which it is desired to pick up is sucked against the cup and, as the latter is lowered, the mica is drawn down with it, substantially as shown in'Fig. 5, flexing around the edge 72 The superimposed sheets above it in the mica stack 70 drag against the abutment 69 and are more or less fanned out substantially as shown when the lowermost sheet is drawn down, where they are accessible to be engaged uponsuccessive actuations of the vacuum cup. The stop or abutment 69 thus prevents more than one sheet of micafrom being pulled out at a time by the members 26. i p

The valve as embodied in the present application of the invention comprises a valve casing or block 76 in which is slidably mounted a valve stem 77, Fig. 4. The valve stem 77 is provided with'a transverse passageway 77 extending through the same, and a longitudinal passageway 7 7 communicating at one end with the central portion of passageway 7 7 andhaving at its opposite end an singularly-arranged passageway 77 extending to the block 76. A passage 77 extending through block 76 and leading to the vacuum cap 73* through tube 7 5 is adapted to aline withpassageways 77 and 77 alternately The block has afpa-ssageway 77 therethrough communicating with the atmosphere, and another passageway 77 therethrough communicating withthe vacuum mechanism. Pass ageways 77 'and77 are arranged to aline with passageway'77 alternately. In theposition of the valve stem 77 shown in Fig. 4, the passage 77 'is in alinement with the passage 7 7 communieating with the atmosphere, which, through the tube 75, places the vacuum cup 73 in communication with the atmosphere, whereby the vacuum cup releases the mica sheet immediately after the mica sheet is engaged by any member 26. Whenthe" valve stem with the vacuum apparatus, the cup 73 then being in its raised position. As more fully described herein, the movement of the valve stem is accompanied by a movement of the vacuum cup support 7 3.

The valve stem 77 is controlled by a snap action by mechanism which includes a valve lever 78 extending at an angle from the stem 77 over the base 228. The end oflever 78 adjacent to the valve stem 77 has an ear78 extending between the bifurcations 7 8 (Fig. 3) on the end of the valve stem. Secured to the ear 7 8 is a vertical pin 78 extending upwardly and downwardly throughtransverse slots 78 in the bifurcations 78 The opposite end of lever 78 is pivoted byan ear or pivot 7 8 to a support 7 8 secured to table 228 at a point in a line substantially at right anglesto the axis of stem 77 and passing through or close to pin 78. The movement in opposite directions of the stem 77 and lever 78 is limited by means of stops 7 9 in the path of movement thereof. A- roller support or slide 80 is slidably supported and mounted on the base 228, and has a cam 'roller 81 at its inner end overlying the rotatable table 10 at apoint adjacent its perifery. The slide 80 ismovableback and forth'on a line substantially parallel with the line'of movement of the stem 77. A pair of coil springs 82 are connected to a vertical pin 82* on the slide 80 at pointsv above and below the upper portion thereof as shown in Fig. 5; These springs 82 extend towards the valve stem 77 and are connected to the pin 78 of lever 78 (Fig. 4) at opposite sides of stem 77. The point of connection 82 of the springs 82 tothe slide 80 is such that, in one position of the slide 80, the springs exert a force on the end of lever 78 along a line at one side of pivot 78*, while in another position or opposite position of the slide 80 theline of connection lies on the opposite side of pivot 7 8 I Thus the movement of slide 80 causes the lever 78 to swing one way or the other around its pivot78 with-a snap due to the springs 82and thus quickly actuating the valvestem 7 7 Inthe position shown in Fig. 4, the springs arein such posit-ion relatively to the several pivots as to cause the valve to be thrown to the position shown. As the slide 80 is moved in Y wardly toward the center of table 10 by the mechanism hereinafter described, the springs 82 will be thrown to the opposite side of pivot-78 quickly moving the valve to vacuum applying position. The slide 80 comprises a lower supportin. member 83 slidably mounted upon the base 228-between a pair of spaced guides 84. The 

